A nowcast model for hazardous material spill prevention and response, San Francisco Bay, California

The National Oceanic and Atmospheric Administration (NOAA) installed Physical Oceanography Real-Time System (PORTS) in San Francisco Bay, California to provide real-time observations of tides, tidal currents, and meteorological conditions. PORTS data are used for optimizing vessel operations and for increasing margin of safety for navigation. The real-time data are also used to guide hazardous material spill prevention and response. Furthermore, archived long-term field data are invaluable in other studies of San Francisco Bay ecosystem. Tides and tidal current patterns are quite complex in San Francisco Bay because the geometry and bathymetry of the bay are very complicated. Clearly, limited real-time observations are insufficient to resolve large spatial variabilities of tides and tidal currents in a complex tidal basin such as San Francisco Bay, California. A high-resolution, depth averaged numerical model has been implemented for the Bay. The numerical model has been expanded and modified to operate in a nowcast mode with which the numerical model continuously computes the tides and tidal currents every hour starting from 24 hours before the present time for a total of 48 hours simulation. Data assimilation techniques, which are common in numerical weather predictions, have been adapted to derive boundary conditions for the nowcasting model. The nowcast modeling system integrates emerging technologies used in PORTS for real-time data collection, nowcast numerical modeling techniques, and dissemination of real-time data and the nowcast model results through internet on the World Wide Web. Users can download the nowcasting results for tides and tidal current distributions in San Francisco Bay for their specific applications and/or for further analysis.